I'm in the final stage of my swap. Mine was more of a headache since my frame wasn't designed for a TH400/200-4R crossmember and the fact it was a pontiac mill.
As mentioned,
- You're best bet is to find a donor olds and take everything you can from the carb linkage/brackets to the trans if your current setup doesn't match.
-200-4R crossmember, aftermarket if you plan to run duals obviously.
- if swapping a used Trans be sure to get the correct tv cable length! Be sure your throttle cable bracket will work or get one from a donor Olds. Don't forget to double check how the cable attaches to the carb. I've seen a few different stud styles that can affect geometry and cause cable bind, so you may have to address that too unless you carb is already compatible. I had to buy aftermarket for everything for my application, but you shouldn't have to. There's also universal cables available from TCI (which I also used).
-TCC lockup: I'be seen this accomplished a few different ways. It's been a long time since I've seen a 200C so I can't recall the pin layout on the connector or if it's the same as a 200-4R. There's a ton of write-ups out there for lock-up function, it's just a matter of how much work you want to do and how much you want to spend. I used the B&M lockup kit because I wanted to do it right the first time and have control of my tcc engagement. It costs more, but Ive gotten tired of trying to take the cheap way out just to do it twice in the long run anyway. There's also the cheaper method of utilizing a toggle switch, pressure switch in the trans, brake activated lockup disengagement, etc. It boils down to your liking and what you want to spend. There's a few aftermarket kits or you can piece meal it together if your trying to be frugal.